The electrical properties of carrier transport between lead selenide polycrystallites manipulated by iodine concentration

We provide the carrier transport properties of the polycrystalline PbSe material prepared by iodine concentration manipulation. We discover that the activation energy of the crystallite boundary barrier can be modulated the iodine concentrations. The electronic structure indicates some acceptor energy levels near the valence band at about -0.26 eV below the Fermi level. The temperature dependences of the conductivities with different iodine concentrations over the range 150–360 K reveal that a high crystalline boundary barrier is constructed with the activation energy as high as 108.2 meV induced by iodine treatment to reduce the dark current of the device. The carrier transport will all deviate from the Arrhenius thermally driven behavior below a transition temperature of 217.4 K, indicating the acceptor levels in the polycrystalline PbSe film with p-type surface microlayer. The structural and compositional properties reveal that the activation energy is highly affected by the phase orientations of PbSeO3 (002) and (110). We believe these results will be helpful for understanding the carrier transport across the crystallite boundaries, and may promote the material optimization of the polycrystalline lead chalcogenides in optoelectronics.